Key to the Regional Orders of Mammals


1. Forelimbs modified as wings, canines large and prominent, greatest skull length less than 35 mm: Order Chiroptera (Bats).

1'. Forelimbs not modified as wings; if canines large and prominent, then greatest skull length greater than 35 mm: 2

2. Back covered with bony plates; teeth a row of small, similar pegs: Order Cingulata, Family Dasypodidae, Dasypus novemcinctus (Armadillo).

2'. Back not covered with bony plates, teeth not as above: 3

3. No upper incisors or, if present, teeth bunodont and skull large; feet protected by at least two hooves per foot: Order Artiodactyla (Even-toed Hoofed mammals)

3'. Upper incisors present; if hooves present, then only one per foot: 4

4. Incisors 1/1: Order Rodentia (Rodents).

4'. Incisors more than 1/1: 5

5. Incisors 2/1 (2nd upper incisor behind first incisor); tail length less than ear length: Order Lagomorpha (Rabbits, hares, pikas).

5'. Incisors more than 2/1; if tail length less than ear length (as in bears), then large prominent canines present: 6

6. Upper and lower incisors procumbent, hooklike, and with secondary cusps (when unworn); eyes minute; snout long and pointed and extending well in front of mouth; total length less than 200 mm: Order Soricomorpha (Shrews).

6'. Upper and lower incisors not as described as above; eyes "normal" size; snout not long and pointed, not extending far in front of mouth; total length more than 200 mm: 7

7. Incisors 5/4; tail long, naked, and scaly; ears large and naked: Order Didelphimorphia, Family Didelphidae, Didelphis virginiana (Opossum).

7'. Incisors less than 5/4; tail and ears not as above: 8

8. Canines large and extending well beyond level of other teeth; pentadactyl feet provided with claws: Order Carnivora (Carnivores).

8'. Canines, if present, small and not extending beyond level of other teeth; a single hoof-covered toe on each foot: Order Perissodactyla, Family Equidae, genus Equus (Horses).

Key modified from Findley et al. (1975).


Last Update: 2 Nov 2007